From Elvin:

Disable the normal reading mode as a fall-back method of reading and use only the prefetching mechanism. 
For the case when a request is not satisfied from the first try, we now will continue to prefetch until 
the request is within the blocks read. 
The problem seemed to appear only in the TWebFile plug-in as it was using the same connection for sending 
requests regardless of the thread. From what I understood in xrd things are different and this problem 
didn't appear while reading using the TXNetFile plug-in.
Also change the type of the prefetching thread from a detached one to a joined one as there were some 
issues with synchronization if the main thread finished reading before the worker thread finished prefetching blocks.


git-svn-id: http://root.cern.ch/svn/root/trunk@39458 27541ba8-7e3a-0410-8455-c3a389f83636